Parenteral solutions such as glucose, blood, etc. are conventionally provided in glass or flexible plastic bag containers. Such containers are normally supported in an inverted position for gravity discharge into a receiving body such as a patient. The container is connected to the patient by means of an administration set, i.e. a length of flexible tubing and a needle. The assimilation of the parenteral solution or fluid into the patient's body is slow and varies with the particular fluid. For this reason the flow rate must be closely regulated.
In the past, the flow rate of parenteral fluid has been regulated by pinching the tubing with a clamping device such as a roller clamp. See, for example, U.S. Pat. Nos. 2,595,511; 3,960,149 and 3,094,429. Such prior art clamps vary the internal cross section, or lumens, of the tubing by squeezing the entire width of the tube between a support surface and a roller, or moveable plate. While these prior art clamps are adjustable, small movements of the roller or plate result in large changes in flow rates over the normal range utilized in dispensing parenteral solutions.
The disadvantages of the prior art parenteral fluid flow regulating devices have been overcome by the present invention in which relatively large movements in a control member are required to effect small changes in the flow rate.